Ukraine has said it wants to establish a one-off international tribunal to try Russia’s top regime members for the act of aggression, which could see it issuing an arrest warrant for Vladimir Putin. Andriy Smyrnov, Ukraine’s deputy head of the presidential administration, said on Thursday that Ukraine believed trying Russia separately for the act of aggression, with international participation, would speed up its quest to hold the Russian president and his inner circle accountable. The act of aggression – accepted by UN members as an international crime – cannot be tried by the international criminal court due to lack of jurisdiction, but is considered the gravest international crime because of its subsequent consequences. On Thursday, three people were killed and 23 injured by two Russian attacks in the eastern Ukrainian city of Kharkiv, according to the Kharkiv regional prosecutor’s office. Smyrnov said the act of aggression, for which Ukraine would initiate additional proceedings, was easy to prove, whereas the type of cases that the ICC could try in relation to Ukraine – war crimes, genocide, and crimes against humanity – would take years. “The fact that [Russia] invaded Ukraine with their army is a fact accepted by our international partners,” said Smyrnov. “We hope to have the indictment within three months.” Smirnov said a judgment made by an international tribunal would still go some way towards justice for Ukraine even without the accused in custody. “Already to have an indictment and to have an arrest warrant for Putin, for [Russia’s defence minister Sergei] Shoigu … will be a big step forward in getting justice,” said Anton Korynevych, ambassador-at-large for Ukraine, who is leading talks with international partners on the matter. “They will be claimed and labelled as potential criminals by an international and legitimate tribunal.” “Then, whenever they [travel] to a state which recognises the tribunal, problems for them might arise,” said Korynevych. “Of course, we would be more than happy to see Shoigu in custody, and not only him but all the other guys who made the decision back then, not only in 2022, but in 2014 also,” said Korynevych, who added that in their view, sentencing at the ad hoc tribunal would follow ICC norms. Korynevych, who named The Hague as the potential host city for the tribunal, said he wanted as many international partners to participate as possible in order to legitimise any decision and widen the potential for accountability. “The idea is for it to be open and as international as possible,” he said. Korynevych said several of Ukraine’s international partners had agreed to establish the tribunal. He said, however, that it was too early and too sensitive to name the countries that had agreed. “Yes, Ukrainians will be involved, it will be necessary to have a Ukrainian prosecutor, but we hope the judges will be international,” said Korynevych. Anya Neistat, legal director of the Docket initiative at the Clooney Foundation for Justice, speaking to the Guardian in May, stressed the importance of Ukraine following procedures meticulously so as to avoid the perception of victor’s justice. This week, Ukraine’s president, Volodymyr Zelenskiy, dismissed Ukraine’s prosecutor general, Iryna Venediktova. In Zelenskiy’s nightly address to the nation, he said Venediktova and the head of Ukraine’s intelligence service, Ivan Bakanov, had collaborators in their departments. A source in the presidential administration claimed Venediktova’s actions had damaged Ukraine’s reputation and stymied efforts to release Ukrainian prisoners of war after a Russian soldier was sentenced to life imprisonment after a six-day war crimes trial in May. “Our colleagues in Germany wrote to me asking: ‘Is it possible for a court to listen to all the evidence and to question all the witnesses and reach a judgment in five days?’” said the source, claiming the trial had also seriously hampered efforts to exchange Ukrainian prisoners of war with Russia . Kremlin representatives had subsequently threatened to try all “2,500 Ukrainian prisoners of war who came out of Azovstal, in our own tribunal, before returning the question of a prisoner exchange in three year’s time”, the source claimed. In an interview with CNN, Venediktova said she would not criticise Zelenskiy’s decision, but believed she was dismissed because of realpolitik and because “it may be time to have a prosecutor with other views”.